b6b337ad1c
Introduce the registration of a callback routine that recomputes msg_ctlmni upon memory add / remove. A single notifier block is registered in the hotplug memory chain for all the ipc namespaces. Since the ipc namespaces are not linked together, they have their own notification chain: one notifier_block is defined per ipc namespace. Each time an ipc namespace is created (removed) it registers (unregisters) its notifier block in (from) the ipcns chain. The callback routine registered in the memory chain invokes the ipcns notifier chain with the IPCNS_LOWMEM event. Each callback routine registered in the ipcns namespace, in turn, recomputes msgmni for the owning namespace. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Mingming Cao <cmm@us.ibm.com> Cc: Pierre Peiffer <pierre.peiffer@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
101 lines
2.2 KiB
C
101 lines
2.2 KiB
C
/*
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* linux/ipc/namespace.c
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* Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
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*/
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#include <linux/ipc.h>
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#include <linux/msg.h>
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#include <linux/ipc_namespace.h>
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#include <linux/rcupdate.h>
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#include <linux/nsproxy.h>
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#include <linux/slab.h>
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#include "util.h"
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static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
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{
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struct ipc_namespace *ns;
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ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
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if (ns == NULL)
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return ERR_PTR(-ENOMEM);
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atomic_inc(&nr_ipc_ns);
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sem_init_ns(ns);
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msg_init_ns(ns);
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shm_init_ns(ns);
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register_ipcns_notifier(ns);
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kref_init(&ns->kref);
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return ns;
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}
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struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
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{
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struct ipc_namespace *new_ns;
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BUG_ON(!ns);
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get_ipc_ns(ns);
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if (!(flags & CLONE_NEWIPC))
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return ns;
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new_ns = clone_ipc_ns(ns);
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put_ipc_ns(ns);
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return new_ns;
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}
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/*
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* free_ipcs - free all ipcs of one type
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* @ns: the namespace to remove the ipcs from
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* @ids: the table of ipcs to free
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* @free: the function called to free each individual ipc
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*
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* Called for each kind of ipc when an ipc_namespace exits.
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*/
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void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
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void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
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{
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struct kern_ipc_perm *perm;
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int next_id;
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int total, in_use;
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down_write(&ids->rw_mutex);
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in_use = ids->in_use;
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for (total = 0, next_id = 0; total < in_use; next_id++) {
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perm = idr_find(&ids->ipcs_idr, next_id);
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if (perm == NULL)
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continue;
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ipc_lock_by_ptr(perm);
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free(ns, perm);
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total++;
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}
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up_write(&ids->rw_mutex);
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}
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void free_ipc_ns(struct kref *kref)
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{
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struct ipc_namespace *ns;
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ns = container_of(kref, struct ipc_namespace, kref);
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/*
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* Unregistering the hotplug notifier at the beginning guarantees
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* that the ipc namespace won't be freed while we are inside the
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* callback routine. Since the blocking_notifier_chain_XXX routines
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* hold a rw lock on the notifier list, unregister_ipcns_notifier()
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* won't take the rw lock before blocking_notifier_call_chain() has
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* released the rd lock.
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*/
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unregister_ipcns_notifier(ns);
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sem_exit_ns(ns);
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msg_exit_ns(ns);
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shm_exit_ns(ns);
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kfree(ns);
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atomic_dec(&nr_ipc_ns);
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}
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